The proposed work is a continuation of an ongoing project to more fully characterize the major catalytic components of the insect microsomal mixed-function oxidase system. Emphasis during the next grant period will be placed on the solubilization and purification of the native form (detergent-solubilized) of NADPH-cytochrome P-450 reductase from the larval midgut tissues of the southern armyworm (Spodoptera eridania) and further attempts will be made to purify cytochrome P-450 itself. In addition, a detailed study will be conducted to more clearly define the characteristics of the mixed-function oxidases induced by a variety of compounds, special emphasis being placed on the induction of multiple forms of cytochrome P-450 with different catalytic capabilities. This study will involve the measurement of various oxidative parameters and levels of microsomal components following dietary treatment of larvae with materials known to induce different forms of cytochrome P-450 in mammals.